Why are there lines at the bottom of my DVD-Rs???

A friend has some DVD-Rs and we are watching them on his laptop. At the bottom of most of them, there is a few lines of what appears to some kind of interference or something. Does anyone happen to know why this is like this? I have seen this on MPGs I have downloaded from the internet that were recorded from VH1 Classic, but not sure if they were sourced from VHS first. He thought it might be the way the VHS was before it was transfered, but virtually everyone is like that.

Thanks,
BOB

 

That's just the overscan area from a video source. You are seeing the entire frame on a PC or laptop but the edges are cut off on a TV so you lose something like 7% of the frame.

It's normal so far as I know and no reason for concern.